## Summary

Performs an arithmetic operation between two rasters or between a raster and a scalar and returns a raster object with the operation applied.

## Discussion

For more information about how this function works, see the Arithmetic raster function.

## Syntax

Arithmetic (raster1, raster2, {operation_type}, {extent_type}, {cellsize_type})

Parameter | Explanation | Data Type |

raster1 | The first input raster. This can be a scalar raster where all pixels have the same value. | Raster |

raster2 | The second input raster. This can be a scalar raster where all pixels have the same value. | Raster |

operation_type | The arithmetic operation to apply between the two input rasters. - Divide —Outputs the divisible result between the corresponding pixel values for each raster.
- Minus —Outputs the difference between the corresponding pixel values for each raster. This operation can be used to calculate change detection.
- Mode —Outputs the pixel value of all overlapping pixels that occurs the most. For example, if there are six bands in a raster, there will be six overlapping pixels. For the values 4, 5, 6, 4, 7, 9, the mode value is 4.
- Multiply —Outputs the product of the corresponding pixel values for each raster. This operation can be used to perform some cost functions.
- Plus —Outputs the sum of all the corresponding pixel values for each raster.
- Power —Outputs the product of the corresponding pixel values raised to the power of the input raster or scalar.
(The default value is Plus) | String |

extent_type | The method to use to compute the extent of the output when the input rasters have different extents. - FirstOf —The output extent is defined using the extent of the first input raster.
- LastOf —The output extent is defined using the extent of the last input raster.
- IntersectionOf —The output extent is defined as the intersecting area of the input rasters.
- UnionOf —The output extent is defined as the total extent of the input rasters.
(The default value is FirstOf) | String |

cellsize_type | The method to use to compute the cell size of the output when the input rasters have different cell sizes. - FirstOf —The output cell size is defined using the cell size of the first input raster.
- LastOf —The output cell size is defined using the cell size of the last input raster.
- MaxOf —The output cell size is defined using the maximum cell size of the input rasters.
- MeanOf —The output cell size is defined using the mean of both input rasters.
- MinOf —The output cell size is defined using the minimum cell size of the input rasters.
(The default value is FirstOf) | String |

Data Type | Explanation |

Raster | The output raster with the arithmetic operation applied. |

## Code sample

Multiplies two rasters and uses the total extent of the inputs.

```
import arcpy
new_raster = arcpy.ia.Arithmetic("Raster1.tif","Raster2.tif", "Multiply", "UnionOf", "FirstOf")
```